10 June 2024

Between the glory of woodland spring ephemerals and summer’s splash of native field flowers, June has fewer blooming natives. On a walk yesterday along the Three Rivers Heritage Trail near Millvale I found a host of pretty flowers, many of them invasive.

Orange day-lily (Hemerocallis fulva) is native to Asia and well established in Pennsylvania. You’ll see it blooming in ditches, along railroad tracks and in gardens. It pops up in so many places that it has at least 10 common names. Orange day-lily is considered invasive in Pennsylvania because its tubers create thick clumps that crowd out native plants in sensitive habitats.

Japanese knotweed (Reynoutria japonica) is listed as one of the world’s worst invasive species. Right now its flowers have just opened in southwestern PA. By the end of summer the flowers will be in long, sweet-smelling racemes, a favorite of bees and butterflies.

Crown vetch (Securigera varia), native to Eurasia and Africa, is in now full bloom. Read about its invasive qualities here.

What’s that popcorn-like smell? It’s poison hemlock (Conium maculatum) and it’s in bloom. You won’t want this plant anywhere you find it. Here’s how to get rid of it; expect a multi-year effort.)

(all photos by Kate St. John)